华南赤红壤无机复合肥氮磷淋失特征

Leaching characteristics of nitrogen and phosphorus in inorganic compound fertilizer from latosolic red soil in South China.

采用室内土柱淋溶模拟试验,研究了不同施肥水平下无机复合肥中氮和磷在华南赤红壤中的淋失特征.结果表明： 铵态氮、硝态氮和总氮淋失量均随施肥量增加而提高;肥料中氮的淋失率在36.8%～49.2%之间,总氮淋失量（y）与施肥量（x）之间的回归方程为y=0.3667x＋66.483（R^2=0.992）;铵态氮和总氮的淋失主要集中在前5次淋洗,硝态氮的淋失持续时间更长.施肥量对可溶性磷淋失量无显著影响,但颗粒磷和总磷淋失量均随施肥量增加呈上升趋势;肥料磷淋失率在0.002%～0.010%之间,总磷淋失量（y）与施肥量（x）之间的回归方程为y=7e^-5x＋0.0538（R^2=0.931）;磷的淋失动态与氮显著不同,为缓慢的持续累积过程.硝态氮与铵态氮淋失量比值和可溶性磷与颗粒磷淋失量比值均随施肥量增加呈下降趋势.

A soil column experiment was conducted to investigate the leaching characteristics of nitrogen and phosphorus in inorganic compound fertilizer from latosolic red soil in South China. The results revealed that the leaching loss of soil total nitrogen （ TN ） , NH4 ^＋ -N and NO3-N was increased with increasing application rate of inorganic compound fertilizer, and 36. 8%-49. 2% of fertilizer nitrogen was lost with leaching water. The regression equation of TN loss （y） and N application rate （x） was y =0. 3667x ＋66. 483 （R^2 =0. 992）. TN and NH4^＋ -N losses mainly occurred in the first 5 leaching events, while NO3 --N loss continued to be significant till the 9th leaching event. Fertilization rate had no obvious impact on soil dissolved phosphorus （ DP）, but the leaching loss of total phosphorus （TP） and particulate phosphorus （PP） was increased with increasing ferti- lization rate. The fertilizer phosphorus loss was within the range of 0. 002% -0. 01% , and the regression equation of TP loss （y） and P application rate （x） was y = 7e^-5x ＋ 0. 0538 （ R^2 = 0. 931 ）. Quite different from that of N, the leaching loss of P was a slow and continuous process. Both the leaching loss of NO3 - -N / NH4^＋ -N and of DP/PP was decreased with increasing fertilization rate.